1. Field of the Invention
This invention relates to the field of cosmetics products, specifically to the field of liquid nail polish removers.
2. Background
The following description is provided solely to assist the understanding of the reader. None of the references cited are admitted to be prior art to the present invention.
Organic solvent-based products have been marketed for many years for removing nail polishes from fingernails and toenails. In recent years, water-based nail polishes have also emerged, and are removed using similar solvent-containing products. For reasons of economy and efficacy, the most common solvent systems used to remove such nail polishes (also known as lacquers) have been acetone and ethyl acetate. However, many problems including skin irritation, and skin and cuticle desiccation are associated with the use of these solvents, and many patents have been issued to remediate these problems.
For example, Curtis (U.S. Pat. No. 4,485,037) describes an aqueous acetone-based nail polish remover whose tendency to remove water from the fingernail and skin is reduced by incorporating an amine salt of a fatty acid amide of a hydrolyzed collagen, and a fatty acid-substituted trialkylamine cationic surfactant. Hofmann (U.S. Pat. No. 4,824,662) describes an acetone or ethyl acetate solvent-based nail polish remover containing a surfactant and an amidoamine salt of hydrolyzed soy protein to reduce the skin and nail water removal properties of the solvent. Hofmann (U.S. Pat. No. 5,077,038) also describes an acetone and/or ethyl acetate-based nail polish remover in which the solvent concentration is limited to approximately 60-80% by weight, and water is added (approximately 20-40% by weight). The salt of a hydrolyzed soy protein and cocamidopropyl dimethylamine propionate are added to prevent drying of the nail and surrounding skin.
Helioff et al. (U.S. Pat. No. 5,024,779) describe a creamy viscous nail polish remover based upon acetone, methyl ethyl ketone, ethyl acetate, and/or butyrolactone, and containing up to about 3% by weight of neutralized crosslinked maleic anhydride-alkyl vinyl ether copolymer gel, and a humectant. Day (U.S. Pat. No. 4,804,486) describes a cream-like nail polish remover utilizing gamma-butyrolactone solvent, and a neutralized acrylic acid-type gelling agent. Remz et al. (U.S. Pat. No. 5,294,435) describe an acetone-based nail polish remover containing a conditioning agent, e.g., stearic acid and triethanolamine, and a suspending agent, e.g., styrene methacrylic polymer, to avoid precipitation of the conditioner. Miner et al. (U.S. Pat. No. 5,342,536) describe an acetone-based nail polish remover that includes gelatin and also glycerin to hold the gelatin in suspension. Faryniarz et al. (U.S. Pat. No. 5,486,305) describe an acetone and/or ethyl acetate-based nail polish remover which contains a diester compound, and a humectant and emollient for conditioning the cuticle and nails. Appell (U.S. Pat. No. 5,027,839) describes a device to protect the skin from irritation caused by these nail polish remover solvents.
Solvent systems other than acetone and ethyl acetate have been described in the patent literature for nail polish lacquer removers, but have met with limited commercial success. These alternative systems have distinct drawbacks including health risks and environmental toxicity problems. For example, Adams (U.S. Pat. No. 4,543,206) describes a non-flammable methylene chloride-based liquid solvent system. There is a health risk associated with inhalation of methylene chloride, and environmental disposal of chlorinated hydrocarbons poses a problem. Dotolo et al. (U.S. Pat. No. 5,346,652) describe a non-aqueous fingernail polish remover based upon a d-limonene, N-methyl pyrrolidone (abbreviated NMP), and cetyl acetate solvent system. However, d-limonene is harmful if swallowed, can be irritating, causes drying, reddening, and sensitization of the skin, and is moderately to highly irritating to the eyes (MSDS, d-limonene, Florida Chemical Co., Inc., Winter Haven, Fla.). Moreover, NMP is now listed an environmentally contaminating toxic solvent under the U.S. Environmental Protection Agency (abbreviated EPA) regulations, and is so-listed (SARA Title III, sec. 313). Similarly, Bayless (U.S. Pat. No. 5,372,742) describes a non-aqueous liquid cleaner suited for removing nail polish, based upon d-limonene, ethyl lactate, and cetyl acetate.
Several patents have focussed on thickener or gelling systems for nail polish lacquer removers. For example, Minton et al. (U.S. Pat. No. 4,197,212) describe an acetone or ethyl acetate-based nail polish remover which contains a hydroxypropyl cellulose acetate gelling agent which provides a Brookfield viscosity of 1,000 to 10,000 cp, and which leaves a beneficial residual film on the nail. Miner (U.S. Pat. No. 5,543,085) describes a thickened laquer-remover such as acetone-ethyl acetate thickened with an acrylate/vinyl acetate polymer, in which an electrolyte is added to the formulation to avoid a slimy or tacky residue on the nail and finger upon solvent evaporation.
As discussed above, several non-acetone/ethyl acetate organic solvents, including chlorinated hydrocarbons, N-methylpyrrolidone (NMP), and d-limonene, have been previously suggested for use in nail polish removers. However, these solvents have been either listed as pollutants on the HAP and/or SARA lists of the EPA, or have been implicated as toxic substances, respiratory irritants, skin irritants, or skin sensitizers, and consequently are relatively undesirable for use in consumer products. While the common EPA-unlisted solvents including acetone and ethyl acetate are currently used in most nail polish remover products, they are undesirable for several reasons including their unpleasant smell, their vapors being irritating to the eyes, their excessive volatility, and their being desiccating and irritating to the cuticle and skin around the nail. Acetone is also known to cause bronchial irritation, and skin erythema via topical exposure.
Among recent patents for nail polish removing compositions, the following are typical of compositions which utilize acetone or ethyl acetate as the primary active solvent: U.S. Pat. No. 5,543,085 by Miner, U.S. Pat. No. 5,486,305 by Faryniarz et al., U.S. Pat. No. 5,342,536 by Miner et al., U.S. Pat. No. 5,294,435 by Remz et al., U.S. Pat. No. 5,024,779 by Helioff et al., U.S. Pat. No. 5,077,038 by Hofmann, U.S. Pat. No. 4,824,662 by Hofmann, U.S. Pat. No. 4,485,037 by Curtis, and U.S. Pat. No. 4,197,212 by Minton et al.